81021648 has 40 divisors (see below), whose sum is σ = 209634400. Its totient is φ = 26964864.

The previous prime is 81021623. The next prime is 81021653. The reversal of 81021648 is 84612018.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 50523 + ... + 52101.

It is an arithmetic number, because the mean of its divisors is an integer number (5240860).

Almost surely, 2^81021648 is an apocalyptic number.

It is an amenable number.

81021648 is an abundant number, since it is smaller than the sum of its proper divisors (128612752).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81021648 is a wasteful number, since it uses less digits than its factorization.

81021648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2659 (or 2653 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 30.

The square root of 81021648 is about 9001.2025863215. The cubic root of 81021648 is about 432.7134131140.

The spelling of 81021648 in words is "eighty-one million, twenty-one thousand, six hundred forty-eight".